6 void factorvm::reset_datastack()
8 ds = ds_bot - sizeof(cell);
11 void factorvm::reset_retainstack()
13 rs = rs_bot - sizeof(cell);
16 static const cell stack_reserved = (64 * sizeof(cell));
18 void factorvm::fix_stacks()
20 if(ds + sizeof(cell) < ds_bot || ds + stack_reserved >= ds_top) reset_datastack();
21 if(rs + sizeof(cell) < rs_bot || rs + stack_reserved >= rs_top) reset_retainstack();
24 /* called before entry into foreign C code. Note that ds and rs might
25 be stored in registers, so callbacks must save and restore the correct values */
26 void factorvm::save_stacks()
30 stack_chain->datastack = ds;
31 stack_chain->retainstack = rs;
35 context *factorvm::alloc_context()
41 new_context = unused_contexts;
42 unused_contexts = unused_contexts->next;
46 new_context = (context *)safe_malloc(sizeof(context));
47 new_context->datastack_region = alloc_segment(ds_size);
48 new_context->retainstack_region = alloc_segment(rs_size);
54 void factorvm::dealloc_context(context *old_context)
56 old_context->next = unused_contexts;
57 unused_contexts = old_context;
60 /* called on entry into a compiled callback */
61 void factorvm::nest_stacks()
63 context *new_context = alloc_context();
65 new_context->callstack_bottom = (stack_frame *)-1;
66 new_context->callstack_top = (stack_frame *)-1;
68 /* note that these register values are not necessarily valid stack
69 pointers. they are merely saved non-volatile registers, and are
70 restored in unnest_stacks(). consider this scenario:
71 - factor code calls C function
72 - C function saves ds/cs registers (since they're non-volatile)
73 - C function clobbers them
74 - C function calls Factor callback
75 - Factor callback returns
76 - C function restores registers
77 - C function returns to Factor code */
78 new_context->datastack_save = ds;
79 new_context->retainstack_save = rs;
81 /* save per-callback userenv */
82 new_context->current_callback_save = userenv[CURRENT_CALLBACK_ENV];
83 new_context->catchstack_save = userenv[CATCHSTACK_ENV];
85 new_context->next = stack_chain;
86 stack_chain = new_context;
92 void nest_stacks(factorvm *myvm)
95 return VM_PTR->nest_stacks();
98 /* called when leaving a compiled callback */
99 void factorvm::unnest_stacks()
101 ds = stack_chain->datastack_save;
102 rs = stack_chain->retainstack_save;
104 /* restore per-callback userenv */
105 userenv[CURRENT_CALLBACK_ENV] = stack_chain->current_callback_save;
106 userenv[CATCHSTACK_ENV] = stack_chain->catchstack_save;
108 context *old_stacks = stack_chain;
109 stack_chain = old_stacks->next;
110 dealloc_context(old_stacks);
113 void unnest_stacks(factorvm *myvm)
116 return VM_PTR->unnest_stacks();
119 /* called on startup */
120 void factorvm::init_stacks(cell ds_size_, cell rs_size_)
125 unused_contexts = NULL;
128 bool factorvm::stack_to_array(cell bottom, cell top)
130 fixnum depth = (fixnum)(top - bottom + sizeof(cell));
136 array *a = allot_array_internal<array>(depth / sizeof(cell));
137 memcpy(a + 1,(void*)bottom,depth);
138 dpush(tag<array>(a));
143 inline void factorvm::primitive_datastack()
145 if(!stack_to_array(ds_bot,ds))
146 general_error(ERROR_DS_UNDERFLOW,F,F,NULL);
151 PRIMITIVE_GETVM()->primitive_datastack();
154 inline void factorvm::primitive_retainstack()
156 if(!stack_to_array(rs_bot,rs))
157 general_error(ERROR_RS_UNDERFLOW,F,F,NULL);
160 PRIMITIVE(retainstack)
162 PRIMITIVE_GETVM()->primitive_retainstack();
165 /* returns pointer to top of stack */
166 cell factorvm::array_to_stack(array *array, cell bottom)
168 cell depth = array_capacity(array) * sizeof(cell);
169 memcpy((void*)bottom,array + 1,depth);
170 return bottom + depth - sizeof(cell);
173 inline void factorvm::primitive_set_datastack()
175 ds = array_to_stack(untag_check<array>(dpop()),ds_bot);
178 PRIMITIVE(set_datastack)
180 PRIMITIVE_GETVM()->primitive_set_datastack();
183 inline void factorvm::primitive_set_retainstack()
185 rs = array_to_stack(untag_check<array>(dpop()),rs_bot);
188 PRIMITIVE(set_retainstack)
190 PRIMITIVE_GETVM()->primitive_set_retainstack();
193 /* Used to implement call( */
194 inline void factorvm::primitive_check_datastack()
196 fixnum out = to_fixnum(dpop());
197 fixnum in = to_fixnum(dpop());
198 fixnum height = out - in;
199 array *saved_datastack = untag_check<array>(dpop());
200 fixnum saved_height = array_capacity(saved_datastack);
201 fixnum current_height = (ds - ds_bot + sizeof(cell)) / sizeof(cell);
202 if(current_height - height != saved_height)
207 for(i = 0; i < saved_height - in; i++)
209 if(((cell *)ds_bot)[i] != array_nth(saved_datastack,i))
219 PRIMITIVE(check_datastack)
221 PRIMITIVE_GETVM()->primitive_check_datastack();